1. Field of the Invention
The present invention relates to a bag and more particularly a gazette bag with a bottom which is square with folds provided on both sides, and also a container such as a carton container for containing milks or juices.
2. Description of the Prior Art
FIG. 37 through FIG. 46 show a manufacturing method of a conventional square bottom bag.
As shown in FIG. 37, the right side brim 102 and the left side brim 103 of a square shaped bag material 101 made of paper, plastic film and the like may be pasted together. The internal face of lower brim section 104 may then be pasted up by folding it upward along the folded line 105 in a horizontal direction to bond portion 107 to the surface 106 of bag material 101 as shown in FIG. 38. This folded and bonded section is folded further upward as shown in FIG. 39. Portion 107 is bonded to the surface 106 of bag material 101 to form the bottom face bonded section 108. The upper brim 109 side of bag material 101 is opened into a square form such that the bottom bonded section 108 is horizontal as shown in FIG. 40. The lateral face 110 is formed and the lateral face 114 to form a perpendicular plane face up to its top portion. This may be done by folding upward both the sides of the bottom bonded section to also form a square shaped bottom face 111, then by folding the lower section of lateral face 110 into the bottom face 111 side from the folded line 112 to bond the bottom face 111, and then a square bottom bag having a square shaped bottom face 111 whose upper brim 109 is opened to a square shape can be obtained as shown in FIG. 41.
Moreover, another manufacturing method of a conventional square bottom bag is generally known. This bag is formed by overlapping the left side brim 102 and the right side brim 103 of a square shaped bag material 102 to past them up together as illustrated in FIG. 37. The bag is then folded such that the whole bag may become a square shaped cylindrical form. The lower section of surface 106 is then folded into a trapezoid while folding the lower section of lateral side 110 horizontally toward the inside as shown in FIG. 42. The lower trapezoidal section of surface 106 is then folded inwardly along the folded line 113 to paste it together. This forms a square bottom bag having a square shaped bottom face 114 with upper brim 109 opened to a square shape as illustrated in FIG. 43.
Still another manufacturing method of a conventional square bottom bag is generally known. This bag is formed by overlapping the left side brim 102 and the right side brim 103 of a square shaped bag material 101 to past them up together as shown FIG. 37. The bag is then folded such that the whole bag may become a square shaped cylindrical form. This is done by folding inwardly the ends while providing the fold 115 running in a vertical direction at the center of the lower section of the lateral face 110 as shown in FIG. 44. The lower brims 104 of surface 106 are brought closer mutually to each other to bond them together and form the bottom face bonded section 116 as illustrated in FIG. 45. At the next step, the bottom bonded section 116 is folded horizontally as shown in FIG. 46 in such a manner that the lower portion of surface 106 may become horizontal and bond the lower section of surface 106. This method forms a square bottom bag having a square-shaped bottom 117 with an upper brim which is opened to a square shape as shown in FIG. 46.
However, according to the above discussed methods the overlapped areas (sealed areas) join to form the bottom face in any of the aforementioned square bottom bags, resulting in the possibility that the bag not only becomes unstable when it is erected but that liquid may also leak from the sealed areas.
In addition, in the case of material such as paper, aluminum foil, or nylon and polypropylene and the like, a low fusion point film like polyethylene having a heat sealing property is laminated on the material in the process of manufacturing the square bottom bags, such that the content of a filled bag may get into direct contact with these laminated films. This contact is an undesirable result according to the prior art methods. Also, the manufacturing machines and operation may become complex because the bag is to be folded intricately as described above.